It is increasingly common for users or "clients" having individual microcomputers interconnected by an institutional intranet or local area network to gain access to various remote sites (such as those on the "World Wide Web") via the well known Internet Communications Network. Clients, using stand-alone microcomputers with a user interface and a resident web browser application, receive and manipulate data from various web sites as desired. In a basic network communication arrangement, all clients are free to access any remote web sites for which Uniform Resource Locator (URL) addresses are available.
Additionally, it is increasingly common in network applications to provide the local network or intranet with a so-called proxy cache server that links the local network with the wider external Internet. The purpose of the proxy cache server is to store and distribute to clients information received from external web sites. The information, which can consist of a web page or associated data, can be accessed by local network clients without making a further connection to the external Internet. The proxy cache server accesses stored web pages based upon addresses provided by clients. These addresses are typically provided in Transmission Control Protocol/internet Protocol (TCP/IP) format, which is commonly recognized by the Internet. The local network, itself, can communicate using an IP protocol or the commercially available IPX protocol by Novell, Inc. of Provo, Utah. In an unregulated proxy cache server environment, request for new web site information cause the proxy cache server to communicate with the Internet, receive and download the newly requested information and store it for further use. Various parameters are used to regulate the length of time for which web site information is stored within the proxy cache server and for when information is deleted. In general, a proxy cache server reduces the number of times Internet connections must be made, particularly for popular, often-visited web sites.
In many institutional settings, unlimited access to web sites is undesirable. Similarly, it may be desirable to limit access to web site information to certain specified users and/or limit specified users to only certain types or categories of web sites. Applications resident in web servers are currently employed to restrict access to specified sites.
In general, however, proxy cache servers are not provided with applications for limiting access by certain users. Hence, all users on the network typically have access to any web site information stored within a proxy cache server. It is therefore, an object of this invention to provide a system and method for limiting access to web site information stored on a proxy cache server within a local area network or intranet. The arrangement should automatically restrict access by unauthorized users to specified web information stored in the proxy cache server and should prevent the proxy cache server from retrieving web site information via the Internet for such unauthorized users.